Background:Human activities contribute to climate change by causing changes in the Earth's atmosphere through emitted amounts of greenhouse gases (GHGs), particles called atmospheric aerosols. Objective: This study takes on the characterization of aerosol types by analysis of photometric data of AERONET network in West Africa. Methods: Two optical parameters are considered in this study: aerosol optical thickness, given to wavelengthl = 440 nm, noticed t440, and Angström coefficient communally named Angström exponent, given in the spectral interval 440-870 nm, noticed a440-870. The considered data in this study correspond to six photometric sites from the worldwide network AERONET in West Africa. These sites are, sites of Agoufou, Banizoumbou, Cap-Verde, Dakar, IER_Cinzana, and Ilorin. The results of study indicate larges variabilities observed of t440 and a440-870 variations for the whole of the six photometric sites. Results: results indicate that the atmosphere over the West African region is constituted by a mixture of aerosols of two modes, coarse mode and accumulation mode. The aerosols of coarse mode are issue from mineral dust locally generated and reinforced by desert dust from Sahara. Conclusion: The aerosols of accumulation mode are issue from anthropic activities, in particularly biomass burning activities, transport, and agriculture, and from others socio-economic activities managed in the region. Keywords: Atmospheric aerosols, AERONET, aerosol optical thickness, Angström coefficient, coarse mode, accumulation mode, mineral dust, biomass burning.